Surveying apparatus.



A. W. MACMILLAN.

SURVEYING APPARATUS.

n um APPLlCATON FILED PR. 5,197- 1;) l ,1 O 1 FMQH lamme@ Jim. @31518.

2 SHEETS-SHEET 2.

A. W. MACMILLAN.

SURVEYING APPARATUS.

APPLICATION FILED APH.6, 191?.

Eaten-te@ 32m. Q,

I! SHEETS-SHEET ARTHUR W. MACMILLAN, OF CHICAGO, ILLENOIS.

SURVEYING APPARATUS.

Application tiled April 6, 1917.

To all whom it may Concern Be it known that l, ARTHUR W. Mao- MiLLAN, acitizenV of the United States, residing at Chicago, in the county ofCook and State of Illinois, have invented certa-in new and usefulImprovements in Surveying Apparatus, of which the following is aspecification.

My invention, which relates to improvements in surveying apparatus, isparticularly adapted ttor measuring distances and heights.

T he principal objects of the invention are, to provide a direct readingdevice which determines distances or heights without laboriousmathematical computations; to provide a device of an exceedingly simpleform and capable of being utilized without the neces sity ot'troublesome manipulations; to provide a portable device of the cha acterdescribed which may be contained within very small compass, therebyenabling it to be carried conveniently in the field; to provide a devicehaving a permanent setting and in which a reading may be takeninstantaneously at will; to provide a device so organized that it may beconveniently adjusted to conform to given data or conditions; to providea single device of the class described which may be used for measuringeither` horizontal or vertical distances; to provide a crevice whichshall be simple in design and inexpensive to manufacture, and, ingeneral, to provide an improved surveying device of the characterdescribed.

ln the drawings, which illustrate specific embodiments ot the invention-Figures l, Q, 3, and el. are diagrams showing` the principle ot theinvention;

Fig. 5 is a perspective view of a single device which may be utilizedfor measuring horizontal or vertical distances, but shown arranged 'forhorizontal measurements;

Fig. 6 is a side elevation ot the device shown in Fig. 5, arranged torshowing vern tical distances;

Fig. 7 is an end elevation of the device shown in Fig. 6, looking fromthe lett-hand side of the ligure;

Fig. 8 is a Jfront side elevation ot a modified form of the deviceparticularly designed Specification of Letters Patent.

Patentedilan. d, 19nd.

SerialNo. 160,124.

4tor use by photographers tor measuring horizontal distances only;

Fig. 9 is a rear side elevation ot the device shown in Fig. 8; and

Fie'. 1O is an end elevation oi' the device shown in Fig. S, lookingfrom the lett of the figure.

ln practising my invention, I malte use of the well known law oftrigonometry that when one side of a right-angle triangle and one of theacute angles of said triangle are known, any other side of the trianglemay bereadily calculated. For obvious reasons, I prefer 'to establish myright-angle triangle in such a position that the sides inclosing theangle of the triangle are in horizontal and in vertical relation.

In Fig. 1, which :illustrates the principle as applied to themeasurement of horizontal distances, the distance AHB represents theheight ot the eye above a horizontal base line B-C, which is thehorizontal distance to he measured between the Observer A and the objectC. It is manifest that the un` known distance B-C may be readily detei1`mined by simply measuring the angle Fim-AWC and making the necessarymathe matical computations. As has been previously stated, one ot 'theprincipal objects ot my invention to avoid the necessitv ot suchcalculations. To this end, l estaliilish etween the eye A and the objectC what in eticct amounts to a triangular ligure having one side DEhorizontal, and another side DMF vertical. As shown in Fig. l, thetriangle D-l-F is interposed between the eye A ot the observer and theobiect C in such relation that the points D, and C are in the samestraight line. lt should be noted iu this connection that it isimmaterial in what position the triangle 20 is to be placed, providedthat it he held in the same position relative to the horizontal and withthe `point D in line with the points A. and C. Having established such atriangle D-E-F in the line ot' sight between the eye A. and the objectC, it will be easily understood that the position oi. the point 21 inthe line E-F corresponds to the ratio between the lengths B-C and ref-B.In this connection, it should be noted that the inclination selected forthe hypotenuse E F may be, and is, arbitrarily selected withoutreference to other data. hence, the distances between the point 2l andthe points E and F bear no direct .tixed ratio to the distances A B andB C, but arc a trigonoi'netrical function thereof.

Having established a predetermined height ot eye A B and an arbitrarytriangle 13,-

E F, l am enabled to make the device direct reading by suitablygraduatingthe line E F so that when the point D ot the triangle D E-F isheld in a line between the eye A of the observer and the object C, the

' If however, the height oi the eve A be changed to G, the datum line GB is changed correspondingly; and if the triangle D E F be held in theposition shown at 22, the line oit' sight G D-C will not intersect thepoint 2l and the reading will be incorrect. It, therefore the samedevice is to be used tor diiierent heights of eye, ditterent sets ofgraduation must be employed tor the hypotenuse E F it the same triangleis to be used.

As an important feature of my invention, I have discovered that thenecessity of supplying different sets of graduations 'for the hypotenuseE F is overcome if the inclination of said hypotenuse E F be changed tocorrespond with the changed height of eye. In F ig. l, H J representsthe original hypotenuse E F with its original graduations unchanged, asshown. so as to establish a ditlierently shaped right-angle trianglesuitable for use with the height G B. It will be observed in this casethat the point 2l' is now in line with the points G, K, and C.

In developingl my invention, the question arose whether the merechanging ot the inclination ot the graduated hypotenuse of my trianglewould. enable the device to be used tor a different eye height tomeasure all horizontal distances, or whether the new condition was truefor only one particular horizontal distance. By mathen'iaticalcalculations li have proved that the graduations on the h vpotenuse E F,it' correct for one height and one inclination of the hypotenuse E F,are correct for all other heights of eye and other horizontal distancesprovided, of course, that the inclination of said hypotenuse E F beadjusted to correspond with the particular height of eye, vthe length ofthe hypotenuse E--F being of course maintained constant. However, forthose who do not care to spend the time necessarv to go into themathematical Jformulae involved in such calculations, l have shown theprinciple proved diagrammatically in Figs. 2 and 3. Fig. 2 shows ahypotenuse ot arbitrary length L M suitably graduated and adjusted atthe proper inclination to correspond with theheight N t) of the eye.When so adjusted, the distances O P and Q are correctly determined byreading the graduations at the points R and S intersected by the line ofsight N P and N Q. lt should be understood that Vthe point M representsthe Zero mark of the hypotenuse scale, and the point L representsinfinity.

Fig. 3 shows the same hypotenuse L M diierently inclined to correspondwith an increased height ot eye T U. By measurement ot Figs. 2 and 3, itwill be found that it' the new inclination of the hypotenuse L M beadjusted to bring the point S, forinstance, in line with the line ofsight between the point T and the same object Q as in Fig. Q, then thepoint .R must also bein line with the object l. hypotenuse, suitablygraduated with a single set of markings, can be used for different eyeheights it the inclination of the hypotenuse be changed to correspond.

ln practice, the most convenient way to'.

establish a right-angle triangle with its legs D E and E F in propervertical and horizontal position, is to suspend the same 'from a pivotalpoint located exactly above the center ot gravity ot the particulardevice employed. This makes it necessary to consider the shifting of thecenter ot' gravity of the hypotenuse L M incident to the changing ot itsinclination to correspond with dili'icrent heights of eye.

Fig. -i is intended to show the loci of various points 23, 2-l and 25 onthe hypotenuse V lV, by which it will be seen that the locus ot thecentral point 2i of the hypotenuse v l/V is in the arc ot' a circledescribed from the sight apex 26. Therefore, by making the hypotenuse VW oi proper dimensions to bring its center of gravity at the centralpoint 24, the correction for the change in the center of gravity. ofsaid hypotemise may be effected by pivotally connecting the point 2l tothe point 26 and placing a counterpoise on the end of an extension otthe link 2& 26 at a suitable distance beyond the point 26.

In Fig. 5, which represents what may be termed a universal type ofdevice, 27 represents the graduated hypotenuse and comprises a smallmetal angle, the upper end ot which is pivotally connected to a shoe 'Q8Hence, the samecapable of sliding movement upon the horizontal trame barThe central point 30 of said hypotenuse bar 27 is pivotally connected tothe end of the bar 29 by means of a link 81, the rear extension 32 ot'which carries a counterweight On the link 3i and at the pivotal axis 3iis mounted a small laterally projectingl horizontal shelf or knife 35provided with a sighting edge 36 precisely coincident with the pivotalaxis 'llie device so far described is suspended in correct vertical andhorizontal position from an upright ilat bar 37, the lower end of whichis secured to the oar 29 by means of a rivet 38 passing exactly throughthe center of gravity of the device. To prevent pivotal m vement or' thesuspending arm 37 and the :functional parts ot' the device, theresilient lower end of the bar 37 is provided with a cone-shapedprojection 39 (see Fig. Y) which enters a small aperture ll() in the bar29, thus making the bar 3l rigid with the other functional parts ot' thedevice. rlllie device as a whole is suspended in vertical position froma linger-piece or handle il, the lower end of which is pivotallyconnected to the upper end ot the bar 37 at i2. lt will be understoodthat the distance between the pivotal point 42 and the center oitgravity 38 is considerable so as to prevent triction of the pivott2 fromseriously interfering with the perpendicularity ot' the apparatus.

When the device is utilized for measuring horizontal distances, the baris swung up into the self-locking position shown in lfig. 5 and the shoe28 is adjusted along the scale 43 to correspond with the height of theeye of the observer above the objective. if the observer is standing ona level street or licor, a remote objective point on the floor levelwill be in the neighborhood or live feet below the eye, depending, ofcourse, on the tallness of the observer. There is sun-.cient friction inthe shoe 28 to prevent improper movement thereof, when once adjusted.rl`he sliding of? the shoe 28 along the bar 29 results in a swingingmovement of the hypotenuse arm 27 and acorresponding pivotal movement ofthe link 3l. However, by r-ason of the t'act that the locus oit thecentral point of the hypotenuse bar the arc of a circle having itscenter at the apex Si, the zero point of the hypotenuse scale move-s ina vertical line below the sight edge 36, the path of movement of saidzero point representing the theoretical vert-ical side of the surveyingtriangle heretofore referred to. Having set the instrument to the heightof the observers eye above the objective, the device is suspended fromthe finger-piece -ll and a sight is taken across the knife edge 36 andto the object. The graduation from the hypotenuse bar 27 intersected bysaid line of sight, represents the horizontal distance between theobserver and the object.

For measuring vertical distances, the same relation and conditionsapply. lt' Figs. l,

2, 3, d, and 5 be turned through an angle oi ninety degrees in ananti-clockwise direction so as to change the former vertical line into ahorizontal base line, and, assuming that such horizontal base line isknown, the graduated hypotenuse is available tor measuring heights in amanner similar to the measurement of the horizontal distances. lVhenusing the device of Fig. 5 for the measurement of heights, thesupporting bar 3T is swung into line with the datum bar 29, as shown in-Figs. 6 and i, the locking projection 39 engaging in the lockingaperture ed in said datum bar 29 so as to inaintain the latter invertical position. Before .measuring distances of the objective abovethe eye, the shoe 28 is of course adjusted along the scale i3 untilthepivotal point of said shoe 2S registers with the graduationcorresponding to the horizontal distance of the eye of the observer-from the objective. The device is then suspended by means of thellinger-piece ll above the eye and between the eye of the observer andthe objective, the height distance being` directly read oli on thehypotenuse bai1 2T.

To those skilled in the art, it will be manif :test that the device maybe modihed readily to permit depiession distances or the object to bemeasured, as well as elevations.

The modification shown in Figs. 8, 9, and l0 is one which l havedesigned especially for use by photographers, in order to enable them toquickly and with reasonable accuracy measure the distance between thecamera and the object which is to be photographed. The device, as shown,is extremely compact and capable of being used with great rapidity. Insaid device, l5 represents a small aluminum casting or stamping havingan angular projection -lG with a sight edge 47. The hypotenuse har 48 isprovided with the customary single scale, `and is pivoted at its upperend onto a small. block 49 adapted to slide in a slot 50, the centerline oi? which is in line with the sighting edge el?. movement ot thelower part of the hypotenuse bar 48 is controlled by means ot a link 5l,the lower end of which is pivotally con-- nected to the hypotenuse barat 52, and the upper end thereof is pivotally connected. to the framepiece 45 at 53. The locations of the pivotal pins 52 and 53 are suchthat for a limited range ot sliding movements ot the block 49, thetheoretical locus oit the point in the theoretical surveying triangle issubstantially coincident with the are described by the lower end of saidlink 51.

lThis is not mathematically accurate, but it The l l) l) is asufficiently close approximation to answer for all practical purposes,the advantages arising from the compactness of the device more thanoutweighing the slight disadvantage caused by its slight deviation tromtheoretical accuracy.

The device is suspended from the fingerpiece 54, the lower end of whichis pivoted at directly above the center of gravity oi the apparatus, sothat the sight edge 47 and the center of the slot 50 lie in a horizontalplane. Coincident with the pivotal pin 53 orp the link 5l, butindependently of the latter, I provide a pointer arm 5G, an intermediatepoint 57 oi which is pivotally connected by means of link 58 to the'rearof the sliding block 49. The end of the pointer 56 cooperates with ascale 59 marked on the back of the instrument and designates heights ofpersons corresponding to eye heights for which the inclination of thehypotenuse bar 48 may be adjusted. The link 5l has an extension 60equipped with a suitable counterweight 6l for compensating for theshitting in the center of gravity of the hypotenuse bar 48 andassociated parts incident to the adjusting of the device to suit personsof different heights. It is understood that the shape of the main trameof the instrument is such that the pivotal point 53 of the link 5l liesin the same vertical line as the center of gravity of the instrument andthe pivotal point 53.

In the event that the terrain is not. level, an artiiicial horizontalcan be established by positioning a target held by an assistant over theobjective in line with the level or infinity point G2 or G3 of thescale. The device having been adjusted for a height distance equal tothe vertical spacing between the upper target and a lower target, asight is then taken at the lower target, and the horizontal distance isread directly from the graduated oblique scale.

Although I have described only two modiiications ot' my invention, itmust be understood that it is capable of being embodied in other formsto suit individual requirements, or for different purposes, withoutsacrifice ot' etliciency. The invention,

' therefore, must be interpreted in a broad sense and is not intended tobe narrowed by the specific details of construction specified, the onlylimitations being those imposed speciically by the prior art or by theexpress language of the claims.

l. In a device of the class described, the combination of a sight, asupport therefor, a scale intersecting the line of sight between theobjective and the observer, and means for maintaining said support andsaidscale in the same angular position relative to the vertical.

Y 2. In apparatus vof the class described,

the combination of a frame provided with a fixed sight, a scale crossingthe line of sight between the observer and an object, the distance ofwhich rom'a known'base line is to be measured and spaced apart from saidsight, and means for maintaining said trame and scale in the sameangular position relative to the vertical and independently of theinclination of the line of sight.

3. In a device of the class described, the combination of a frameprovided with a sight, a scale iXedly connected to and spaced apart fromsaid sight and crossing the line of sight between the eye of theobserver and the object, and suspension means for said frame and scalefor supporting the same temporarily in the line of sight.

4. In a device of the class described, the combination of a frameprovided with a sight and a graduated scale arranged to cross the lineosight between the observer and the object, and means for pivotallysuspending said frame at a point spaced apart from and located above thecenter oi' gravity of said frame.

5. In a device of the class described, the combination of a sightlocated in the line of sight between the eye of the observer and theobject, a scale inclined to the vertical and crossing the line ot sightand provided with gra duations, representing different perpendiculardistances of the object from a base line passing through the eye of theobserver, and means for adjusting the inclination of said scaleaccording to the length of said base line.

6. .In a device of the class described, the combination of a frameprovided with a lixed sight and meansV for pivotally supporting theframe whereby it will always occupy the same position relative to thevertical, a scale movably lmounted on said frame, crossing the line ofsight and capable of being adjusted at various angles to the vertical,and compensating means controlled by movement of said scale relative tosaid frame for maintaining the center of gravity ot the frame andassociated parts in the same position.

7. In a device ot' the class described, the combination of a framemember provided with a sight, a member arranged to slide on said framein line with said sight, a scale having one end connected to'saidsliding member, a link pivotally connecting an intermediate point onsaid scale with a point on said frame substantially coincident with avertical line passing through the center of gravity of said trame, anextension on Said link provided with a counterweight for said scale, andmeans for pivotally supporting said frame at a point vertically aboveits center of gravity.

8. In a device of the class described, the combination of L frame memberprovided `with a sight, a member arranged to slide on said frame in linewith said sight, a scale having one end connected to said slidingmember, e link pivotally connecting an intermediate point on said scalewith a point on said frame Substantially coincident With n verticallinepassing through the center of `gravity of said frame, an extensionon said link provided with a counterweigght for said Scale and means forpivotally supporting said frame at o point vertically above its centerof gravity, seid frame beingprovided with graduations indiczitingg` theextent of movement of said scale.

ARTHUR W. MACMILLAN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

